Release rate testing of drugs is often a very tedious job, partly because samples of the drug must be released in different media and also because the temperature of test tubs containing the different media must be accurately controlled. One traditional way to perform drug release rate testing is to prepare the different media in a number of test tubes and set the test tubes into a water bath or similar water-containing vessel which maintains the test tubes at a predetermined, desired temperature. One current apparatus used in drug release rate testing enables the test tubes to be set in several rows with twelve test tubes per row, with each row of test tubes being filled with fresh media. A motor-driven bar holding twelve sample holders, each containing a sample of the drug being tested, dips the sample holders into a row of twelve test tubes. The sample holders are sequentially dipped into test tubes in each row until the test is complete.
One drawback of this type of apparatus is that some drugs must test for twenty rows, i.e., be dipped into media in twenty test tubes each in one of twenty rows of such test tubes, which results in the test apparatus being large and long, and also requiring a relatively large water tank to hold the warm water to provide for the temperature-controlled water bath. Such an apparatus wastes a considerable amount of energy for testing twelve samples. Space is another problem since more test rows required more bench space.
Another problem concerns the filling of the test media into the test tubes. Since the test media is typically capable of evaporating and any such evaporation may adversely affect the test conditions, the media can only be filled into the test tubes a few minutes before the test, i.e., before the sample holder with the sample of the drug being tested is inserted therein, to avoid evaporation of even a small volume of the test media. Moreover, the test media must be removed from the test tubes and the test tubes cleaned after each test. Before removing the test media, at least some of the test media must be removed from each test tube for analysis. Such an apparatus occupies a relatively large amount of space and wastes energy, and also requires several people to work around it for the release rate test.